Ultimately, Connally narrowly won the nomination in a runoff against Yarborough and then defeated the strong Republican gubernatorial candidate in Texas since 1924, Jack Cox of Houston in the general election. Cox had lost the Democratic nomination to Governor Daniel in the 1960 party primary.[8] In 1964, Cox, a part of the conservative wing of his new party, lost the Republican nomination for the U.S. Senate to George Herbert Walker Bush, also of Houston, and the future vice president and U.S. president.

After his Senate and gubernatorial election defeats, Wilson co-founded the law firm, Wilson, Kendall, Koch, and Randall in Austin. He served from 1969-1971 as the assistant attorney general in charge of the Criminal Division of the Justice Department. Wilson's book A Fool For a Client focuses upon President Nixon's decline, pending impeachment, and ultimate resignation from the Oval Office.[4] The conservative Wilson switched to the Republican Party more than five years before Connally. Ironically, it was Connally, considered a political pragmatist, whom Nixon most highly regarded, having appointed him U.S. Secretary of the Treasury in 1970 and reportedly having considered Connally for the vice-presidential nomination vacated in 1973 by Spiro T. Agnew.[9]

Wilson was married for thirty-six years, until her death, to the former Marjorie Lou Ashcroft (1918–1984).[1] The couple had two children and five grandchildren. Known for his cowboyhumor, Wilson operated two ranches: Brushy Creek in Williamson County and Little River Ranch in Milam County. He served as director of the Brushy Creek and Upper Brushy Creek Water Control Improvement Districts for two decades. He was also chairman of the Cullum and Boren and the Wilson Land and Cattle companies.[3]

Wilson died at the age of ninety-three and was interred on December 17, 2005, alongside his wife in the Patriot's Hill section, Row R, No. 24, of the Texas State Cemetery in Austin.[4]